Hinge Interaction Surface Form

Use the Hinge Interaction Surface form as follows:

Select one of the available options:

    1. The phi factor is set equal to 1.

    2. The maximum compressive axial load is not limited to Pmax.

    3. For the pushover interaction surface, axial tension is positive, and axial compression is negative. This is an opposite sign convention from that used in concrete design, but it is consistent with analysis results.

Refer to ACI 318-02 for additional information.

When the Doubly Symmetric About M2 and M3 check box is checked (which it is by default), input the interaction surface in the (+M2, +M3) quadrant for all values of P (i.e., both positive and negative) in the spreadsheet of the Interaction Surface Definition form (which displays by clicking the Define/Show Surface button). Thus only 90 degrees of the full 360-degree interaction surface is input. Symmetry is used by the program to define the interaction surface in the (–M2, +M3), (–M2, –M3), and (+M2, –M3) quadrants. If the Doubly Symmetric About M2 and M3 check box is unchecked, all 360 degrees of the interaction surface must be input.

The Number of Curves edit box indicates the number of equally spaced P-M curves that will be used to define the interaction surface ( 5 curves is the default). If the Doubly Symmetric About M2 and M3 check box is checked, the curves are equally spaced between 0 and 90 degrees. If the Doubly Symmetric About M2 and M3 box is unchecked, the curves are equally spaced between 0 and 360 degrees.

  image\interact_wmf.gif

Click the Define/Show User Interaction Surface button to open the {Curve} Interaction Surface Definition for {Property Name}  form and define or view the interaction surface curves.

 

Access the Hinge Interaction Surface form as follows:

  1. Click the Define menu >  Section Properties > Frame/Wall Nonlinear Hinge command to access the Define Frame/Wall Hinge Properties form. Then do one of the following:

  1. Ensure that the Force Controlled (Brittle) option has been selected and that an Interacting hinge type (P-M2, PM-3, P-M2-M3) has been selected  from the drop-down list of hinge types.

  2. Click the Modify/Show Hinge Property button to access the Hinge Property Data for {Hinge ID - Interacting [Hinge Type]} form.

  3. Click the Modify/Show {P-M2, PM-3, PMM} Interaction Surface (Capacity) Data button.